<nav >
    <menuAff>
        <ul id="dropdown">
            <li><a href="#" class="parent">Menu</a> 
                <ul class="children">
                    <li><a href="index.php">Accueil</a></li>
                    <li><a href="recherche.php">Recherche</a></li>
                    <li><a href="item.php">Consultation</a></li>
                </ul>
            </li>
        </ul>
    </menuAff>
    <hr class="vertical">
    <script>
        $(document).ready(function () 
        {
            $('#dropdown').hover(
            
                function () 
                {
                    //change the background of parent menu              
                    $('#dropdown li a.parent').addClass('hover');
                    //display the submenu
                    $('#dropdown ul.children').show();
                },
                function () 
                {
                    //change the background of parent menu
                    $('#dropdown li a.parent').removeClass('hover');            
                    //display the submenu
                    $('#dropdown ul.children').hide();
                }
            );
        });
            </script>
        </nav>
<!-- http://www.queness.com/post/966/jquery-drop-down-menu-for-rss-subscription-tutorial-->